Marinate the Cauliflower: In a large container, whisk together water, vegetable stock concentrate, Tikka Masala Sauce, and salt until fully dissolved. Submerge the trimmed cauliflower head in the liquid. Cover and refrigerate for 8–12 hours. Remove cauliflower from brine and pat dry thoroughly.
Season & Roast: Preheat oven to 400°F (205°C). Rub the cauliflower all over with olive oil, cumin, smoked paprika, and turmeric. Place on a parchment-lined sheet pan or cast iron skillet. Tent loosely with foil and roast for 35 minutes. Remove foil and continue roasting for 25–35 minutes, until deeply golden and tender throughout.
Glaze & Serve: During the last 10 minutes of roasting, baste generously with warm Tikka Masala Sauce. Once fully roasted, drizzle with remaining sauce and garnish with chopped cilantro. Serve with optional lime wedges or a yogurt drizzle